With the energy crisis created by the impact of the natural resources shortage, together with the anticipated depletion of the natural resources, a considerable amount of effort has been directed to other forms of energy. Although there are several other forms of energy, the emphasis has been placed on solar energy as the most logical heat source. Consequently there are on the market many so-called solar furnaces.
These prior art devices generally comprise a focusing lens, a medium - either air or liquid - to be heated, in some instances a storage tank, and in other instances a reflective surface such as a mirror and/or a reflector.
Although these solar furnaces are operable and in certain instances commercially operable, they are not without their attendant disadvantages. Principally the problem area is a lack of a sufficient concentration system for the incident solar energy, directivity relative to the angle of the sun, and a storage system with a capacity to carry the system on cloudy days. The problem related to the concentration of the solar energy is with the lens and its reflecting surfaces and the response of the system to the low angles of the sun.
Further, the prior art systems generally utilize the solar radiation to heat either a liquid or air directly and then utilize the heated air or water for the intended purpose. Storage systems are much fewer and are of the indirect type, that is, the heated excess air or liquid is placed in a storage medium. These prior art storage systems are very simple in structure and somewhat crude. Very little advance in the art has been made with storage systems.
Although perhaps in some future period of time solar energy may be a complete substitute for other forms of energy, today solar energy, at best, is a supplement to or an alternate source of energy. Nonetheless, the failure of the prior art to recognize the practical usefullness of solar energy has resulted in commercial systems that are extremely expensive, but, yet, of only a minimal and questionable value.